Positive Health Online

Abstract

PRYOR, The Biodynamics Institute, Louisiana State University, Baton Rouge 70803 USA. wpryor@LSU.edu reviews (244 references!) the evidence regarding the effects of vitamin E on heart disease, comprising basic science, animal studies, epidemiological and observation studies and 4 intervention trials.

Background

Methodology

Results

The results from in vitro, cellular and animal studies, which are impressive in quantity and quality, demonstrate that vitamin E, the most important fat-soluble antioxidant, protects animals against a variety of types of oxidative stress. The hypothesis linking vitamin E with prevention of cardiovascular disease (CVD) postulates that the oxidation of unsaturated lipids in low-density lipoprotein (LDL) particle initiates a complex sequence of events leading to the development of atherosclerotic plaque. This hypothesis is supported by many studies in vitro, in animals and in humans. There is also evidence that the ex vivo oxidizability of a persons LDL is predictive of future heart events. These basis science and observation studies, along with the safety of vitamin E, were the impetus to clinical intervention trials. The three trials which have been reported in detail are, on balance, supportive of the proposal that supplemental vitamin E can reduce heart disease risk. The fourth trial, just reported, showed small, but not statistically significant benefits. Subgroup analyses of cohorts from the older three trials, as well as evidence from smaller trials, demonstrate that vitamin E provides protection against several medical conditions, including those indicative of atherosclerosis, such as intermittent claudication. Vitamin E supplementation is also associated with an improvement in the immune system and protection against diseases apart from CVD, such as prostate cancer. Vitamin E, at the supplemental levels used in the current trials, 100-800 IU/d, is safe, with little likelihood that increased risk exists for those individuals taking supplements. About ½ of American cardiologists take supplemental vitamin E, about the same number that take aspirin. One study suggests that aspirin plus vitamin E is more effective than aspirin alone. There are a substantial number of trials involving vitamin E in progress; however it is likely that each condition for which vitamin E provides benefit will have a unique dose-effect curve. Furthermore, since antioxidants appear to act synergistically, vitamin E may be more effective if combined with other micronutrients. Research determining the specific dose-effect curve for vitamin E for each condition in combination with other micronutrients will be long-winded and difficult to complete.

Conclusion

The scientific community should recognize that there is never a time when the science is complete and that at some point, the weight of the scientific evidence should be judged adequate; we are very close to that time with vitamin E. In view of the very low risk of supplementation with vitamin E, and the difficulty in obtaining more than about 30 IU/day from a balanced diet, some supplementation appears prudent now.

References

Pryor WA. Vitamin E and heart disease: basic science to clinical intervention trials. Free Radical Biology and Medicine 28(1): 141-64. 1 Jan 2000.

Comment

Amen! Said better than I could myself.